Long-term repeatability of behaviours in zebrafish (Danio rerio)

Animal personality is defined as individual variation in behaviour that is consistent over time and/or across contexts. Animal personality is now considered a fundamental aspect in the fields of animal behaviour and behavioural ecology, yet the majority of studies assess repeatability of behaviours over only relatively short time periods (e.g. a week) using just two measures. Understanding whether behavioural traits are repeatable over longer periods is important for the assessment of individual differences in behaviour. Using zebrafish (Danio rerio), we investigated the repeatability of activity and exploratory behaviours, including distance travelled, time spent in the bottom of the arena, stationary time and overall exploration of the novel arena over a 28-week period, using five intervals. All measures were repeatable over 28 weeks, but the repeatability estimates were much lower when comparing the initial week one and week two behaviours. There were clear sex differences in aspects of activity, with males more active than females. Importantly, our behavioural assays suggest that zebrafish require an initial “tank experience,” prior to the main phenotyping session, to ensure that behaviours being measured are repeatable—these effects are often not considered, but have implications for the many studies that measure behaviour at a single time point only.     

Arena behaviour of ewes selected for superior mothering ability differs from that of unselected ewes

As part of a study searching for criteria for the genetic improvement of maternal ability, behavioural parameters were measured in ewes from two flocks, one selected for maternal ability (Fertility Flock), the other unselected (Random Flock). Behaviour was measured in an open-field test prior to mating in 1990 and in an arena test prior to mating in 1990 and 1991, and prior to lambing in 1991.The open-field test consisted of placing the ewes in an enclosed field measuring 16 m × 16 m for a period of 5 min. The field was divided into 16 squares each measuring 4 m × 4 m. The following measures were made: number of squares entered, whether or not the ewe bleated, urinated or defaecated and the number of bleats.The arena test consisted of placing the ewes in an enclosed arena measuring 3 m × 13 m; at one end of the arena there was a pen of sheep, in front of which sat a person. The floor of the arena was marked into 39 squares each measuring 1 m × 1 m. The test lasted 10 min and the following parameters were derived by recording the square in which the animal was located every 15 s; minimum and maximum distance from the person, mean distance from the person and distance travelled. The number of bleats was also recorded for each ewe, as well as whether or not she bleated, urinated or defaecated.There were no differences between the two flocks in any of the parameters measured in the open-field test. However, on all three occasions, there were differences between the two flocks in the total distance travelled and the number of bleats. The coefficients of repeatability of these two parameters, as measured by the intra-class coefficient of correlation, were 0.48 and 0.57 respectively.The results indicate that the arena test measures differences in the behaviour of ewes that differ in maternal ability and may therefore be of use in identifying ewes of superior mothering ability.     

HOW AND WHEN DO LAMBS RECOGNIZE THE BLEATS OF THEIR MOTHERS?

ABSTRACT

In domestic sheep Ovis aries, the mother and the young display a preferential bond for each other that relies on multimodal inter-individual recognition. Lambs show a preference for their own dam shortly after birth, and this is important for their survival. The role of acoustic cues in this early preference for the mother is not clear. The aim of the present work was to analyze the timing of acoustic recognition of the mother and to identify the physical parameters used in the recognition of maternal bleats by the lamb.

In a first study, we investigated the ability of lambs to discriminate between the bleats of their own mother and an alien equivalent mother in a two-choice test. Both ewes were hidden behind a canvas sheet and lambs were not allowed to approach the dams closer than 1 m, thus preventing visual as well as olfactory perception. Tests were conducted 12 hr, 24 hr or 48 hr after birth (n=19 or 20/group). An indication of vocal discrimination was already present at 24 hr and at 48 hr lambs spent significantly more time near their mother than near the alien dam.

In a second step, we investigated which physical parameters of the bleats were important for recognition. For this, we conducted playback experiments with modified bleats at two weeks postpartum. Ours results show that lambs pay attention to a combination of various time, energy and frequency parameters: timbre (distribution of energy within the spectrum), amplitude and frequency modulations appear to be the most important parameters encoding the individual signature.

We conclude that vocal recognition between the ewe and her lamb plays an important role in the display of preferential mother-young bond from very early on. Our studies also demonstrate that the encoding of the individual signature is not limited to the frequency domain but rather involves a multiparametric encoding process.     

Effects of sex, litter size and periconceptional ewe nutrition on the ewe–lamb bond

Undernutrition restricted to the time around conception in sheep alters endocrine and metabolic responses in the offspring. Studies in rats suggest that such an early insult can also alter the behaviour of the offspring. We studied the effects of mild maternal periconceptional undernutrition (10–15% body weight reduction) on the lamb's response to separation from and reunion with the mother, and on the ewe–lamb bond, evaluated as the preference for each other over an alien ewe/lamb in a test enclosure, at 24 h, 1 and 4 weeks of age. Lamb birth weight was not affected by maternal nutrition. Maternal periconceptional undernutrition did not affect the lambs’ responses to separation and reunion (number of vocalisations, times to leave pen and achieve proximity with ewes) or the bond between ewes and lambs (percentage of time spent near their own dam/lamb). However, there were effects of sex, litter size and time on lambs’ responses to separation and reunion and on the ewe–lamb bond. Female lambs vocalised more during separation (P ≤ 0.01) and left the holding pen faster than males (P ≤ 0.05), and twins vocalised more than singletons (P ≤ 0.05). The time to leave the holding pen, achieve proximity with the ewes and number of vocalisations decreased with increasing postnatal age of the lamb (all P ≤ 0.001). Ewes showed a stronger preference for the lamb at 24 h and 1 week than at 4 weeks postpartum (P ≤ 0.001), whereas lambs followed an opposite trend, showing a lower preference for the mother at 24 h and 1 week and increased preference at 4 weeks of age (P ≤ 0.001). We conclude that periconceptional undernutrition does not affect offspring response to separation from the mother or the bond between ewes and lambs, but that these behaviours are affected by sex and litter size for up to 4 weeks after birth.     

Social transmission of physiological and behavioural responses to castration in suckling Merino lambs

In social species like sheep, social context can modify both physiological and behavioural responses to stressors and normal behavioural patterns. Presence of conspecifics can ameliorate responses to noxious stimuli, an effect termed social buffering, whereas the presence of a distressed conspecific can invoke a distress response in an observer animal not receiving a noxious organic insult, an effect termed social contagion. Furthermore, synchrony of normal behaviours can occur within a group. Here a range of social contexts were created by grouping suckling lambs undergoing knife, ring or sham castration treatments either homogeneously or heterogeneously by castration treatment in pens within an animal house. The impact of social grouping on cortisol, rectal temperature, pain avoidance behaviours, postural behaviours and synchrony of behaviour in the first 12 h following castration treatment was examined. Irrespective of castration treatment, lambs grouped homogeneously by castration treatment had higher cortisol concentrations across the four time points measured than lambs grouped heterogeneously. They also spent 1.9% more of the time in restless behaviour in the first 1 h following castration, and in the 12 h following castration spent 6.7% more of their time lying ventrally, 4.9% less time standing normally, 1.6% more time walking normally, and 4.9% less time in total standing postures. Interactions between social grouping and castration treatment were not significant for physiological variables, pain related behaviours or postures with the exception of lateral lying which was decreased in knife castrated lambs grouped heterogeneously with other castration treatments from 1.9% (homogeneous grouping) to 0.4% (heterogeneous group). Synchronisation of behaviour was seen for walking in lambs grouped heterogeneously by castration treatment and for feeding at the trough in lambs grouped homogenously by ring and sham castration treatments. Lying and standing respectively, were negatively synchronised (occurred less frequently than predicted by chance alone) in ring and knife castrated lambs grouped homogeneously. The results indicate that mixing lambs that received the three castration treatments within a pen modified the activity profile of the lambs but did not substantially modify the behavioural or physiological changes that are stigmatic of responses to the specific castration treatments. The social contexts contrasted in the study did not result in marked contagion or social buffering between lambs of the measured responses and did not confound comparison of castration treatments. None-the-less, the comparability of responses observed in castration treatment groups penned homogenously or heterogeneously might not necessarily occur in other classes of sheep or in other social contexts. The absence of social transmission of behavioural and physiological responses indicates that grouping non-castrated lambs with castrated lambs did not compromise the welfare of the non-castrated lambs when their mothers were present.     

Effects of diazepam on the behaviour of weaned pigs in three putative models of anxiety

The present study examined the effects of diazepam (a widely used anxiolytic benzodiazepine) on the behavioural response of pigs to three novel experimental situations used to measure anxiety-related behaviour in rodents. Twelve weaned pigs (two pairs from each of the three litters) were tested in an elevated plus-maze at the age of 6 weeks, a light/dark test at the age of 7 weeks and an open-field test at the age of 8 weeks. Six of the pigs were pre-treated with diazepam (valium) and the other six with saline (control). In the elevated plus-maze, diazepam-treated pigs had a higher number of entries into open arms (P=0.04), spent more time on open arms (P=0.07), and had a higher number of total arm entries (P=0.05) than pigs from the control group. However, diazepam had no significant effects on behaviour in the light/dark test (i.e., latency to enter lit compartment, number of entries into lit compartment and the time spent in lit compartment) or the open-field test (i.e., number of lines crossed, number of entries into centre). In summary, the anxiolytic effects of diazepam on the pigs' behaviour were only demonstrated in the elevated plus-maze, where the time spent on open arms and the number of entries into open arms could be interpreted as measures of anxiety in pigs.     

Effects of the observation method (direct v. from video) and of the presence of an observer on behavioural results in veal calves

This study aimed at assessing the effect of the observation method (direct or from video) and the effect of the presence of an observer on the behavioural results in veal calves kept on a commercial farm. To evaluate the effect of the observation method, 20 pens (four to five calves per pen) were observed by an observer for 60 min (two observation sessions of 30 min) and video-recorded at the same time. To evaluate the effect of the presence of the observer in front of the pen, 24 pens were video-recorded on 4 consecutive days and an observer was present in front of each pen for 60 min (two observation sessions of 30 min) on the third day. Behaviour was recorded using instantaneous scan sampling. For the study of the observer's effect, the analysis was limited to the posture, abnormal oral behaviour and manipulation of substrates. The two observation methods gave similar results for the time spent standing, but different results for all other behaviours. The presence of an observer did not affect the behaviour of calves at day level; however, their behaviour was affected when the observer was actually present in front of the pens. A higher percentage of calves were standing and were manipulating substrate in the presence of the observer, but there was no effect on abnormal oral behaviour. In conclusion, direct observations are a more suitable observation method than observations from video recordings for detailed behaviours in veal calves. The presence of an observer has a short-term effect on certain behaviours of calves that will have to be taken into consideration when monitoring these behaviours.     

Behavioural responses of juvenile Steller sea lions to abdominal surgery: Developing an assessment of post-operative pain

Marking and tracking of marine mammals is required to gain a better understanding of life history traits; however, some marking procedures used are likely painful. Recent technological advances include intra-abdominally implanted archival telemetry devices for the life-long monitoring of individual animals. No research to date has assessed any aspect of post-operative pain in marine mammals. This study specifically evaluated behavioural responses in nine juvenile Steller sea lions to the abdominal surgery required for insertion of telemetry devices. Behaviours predicted to reflect post-operative pain, including posture and body movements, were assessed during 3-day pre-, 3-day post-, and days 10–12 post-surgery. The proportion of time sea lions spent on land standing increased from 0.00 to 0.07 and then decreased to 0.04, for pre-, post-, and late post-surgery respectively. Similarly, the proportion of land time spent with the back arched increased from 0.01 to 0.57, and then decreased to 0.33. The time sea lions spent on land with pressure on their ventral side while sitting or lying down declined from 1.0 pre-surgery to 0.17 post-surgery, and increased to 0.20 late post-surgery. The time sea lions spent in locomotion on land and in the water decreased from 0.05 in pre-surgery to 0.01 post-surgery, and returned to 0.06 by late post-surgery. These results suggest that behaviours such as back arch, standing, time spent with pressure on the ventral side, and locomotion may be useful in the assessment of pain following abdominal surgery in sea lions. The presence of these behaviours and their persistence for up to 12 days after surgery suggest that more work is required to further develop safe and effective analgesic methods for this procedure.     

Relationships between handling,behaviour and stress in lambs at abattoirs

There is community concern about the treatment of farm animals post-farm gate, particularly animal transport and slaughter. Relationships between lamb behavioural and physiological variables on farm, stockperson, dog and lamb behavioural variables pre-slaughter and plasma cortisol, glucose and lactate in lambs post-slaughter were studied in 400 lambs. The lambs were observed in three behavioural tests, novel arena, flight distance to a human and temperament tests, before transport for slaughter. Closed-circuit television video footage was used to record stockperson, dog and lamb behaviour immediately before slaughter. Blood samples for cortisol, glucose and lactate analyses were collected on farm following the three behavioural tests and immediately post-slaughter. The regression models that best predicted plasma cortisol, glucose and lactate concentrations post-slaughter included a mixture of stockperson and dog behavioural variables as well as lamb variables both on-farm and pre-slaughter. These regression models accounted for 33%, 34% and 44% of the variance in plasma cortisol, glucose and lactate concentrations post-slaughter, respectively. Some of the stockperson and dog behaviours pre-slaughter that were predictive of the stress and metabolic variables post-slaughter included the duration of negative stockperson behaviours such as fast locomotion and lifting/pulling lambs, and the duration of dog behaviours such as lunging and barking at the lamb, while some of the predictive lamb behaviour variables included the durations of jumping and fleeing. Some of the physiological and behavioural responses to the behavioural tests on farm were also predictive of the stress and metabolic variables post-slaughter. These relationships support the well-demonstrated effect of handling on fear and stress responses in livestock, and although not direct evidence of causal relationships, highlight the potential benefits of training stockpeople to reduce fear and stress in sheep at abattoirs.     

Phytochemical and biological analysis of Skullcap (Scutellaria lateriflora L.): A medicinal plant with anxiolytic properties

The phytochemistry and biological activity of Scutellaria lateriflora L. (American skullcap) which has been traditionally used as a sedative and to treat various nervous disorders such as anxiety was studied. In vivo animal behaviour trials were performed to test anxiolytic effects in rats orally administered S. laterifolia extracts. Significant increases in the number of entries into the center of an "open-field arena"; number of unprotected head dips, number of entries and the length of time spent on the open arms of the Elevated Plus-Maze were found. The identification and quantification of the flavonoid, baicalin in a 50% EtOH extract (40 mg/g) and its aglycone baicalein in a 95% EtOH extract (33 mg/g), as well as the amino acids GABA in H2O and EtOH extracts (approximately 1.6 mg/g) and glutamine in a H2O extract (31 mg/g), was performed using HPLC. These compounds may play a role in anxiolytic activity since baicalin and baicalein are known to bind to the benzodiazepine site of the GABAA receptor and since GABA is the main inhibitory neurotransmitter.     

The effects of pasture availability for twin- and triplet-bearing ewes in mid and late pregnancy on ewe and lamb behaviour 12 to 24 h after birth

This experiment was conducted to evaluate the effect of offering ewes two different feeding levels, during mid and late pregnancy, on ewe and lamb behaviour 12 to 24 h after birth. Romney ewes, bearing twin (n = 80) or triplet foetuses (n = 56), were allocated to a pasture sward height of 2 or 4 cm between 70 and 107 days of pregnancy. In late pregnancy (day 107 to 147), half of the ewes were reallocated the alternate sward height, which produced four treatments: 2-2, 2-4, 4-2 and 4-4. Ewes were weighed on days 65, 92, 107 and 130 of pregnancy and lamb live weights were recorded 12 to 24 h after birth. Twelve to 24 h after birth the maternal behaviour score (MBS) of the ewes were determined, whilst their lambs were tagged. After the lambs were released, the behaviour of each ewe and her lambs was observed for 5 min. Ewe treatment and litter size had no effect on ewe MBS. However, as MBS increased (ewes stayed closer to lambs during tagging), ewes bleated less in a high-pitch and were quicker to make contact with their lamb. During the observation period, ewes in the 4-4 treatment had a greater percentage of their bleats in a low pitch (P < 0.05) than ewes in the 2-2 and 4-2 treatment (61.3% v. 41.3% and 38.8% low bleats, respectively) and more lambs born to 4-4 ewes (95%) bleated than lambs born to 2-2 ewes (84%; P < 0.05). However, lambs born to ewes in the 2-2 treatment bleated earlier than lambs in all other treatments (P < 0.05). Lambs born to 4-4 ewes were less likely (P < 0.05) to move towards their dam in order to make contact than lambs born to 2-2 or 4-2 ewes (3.1% v. 16.9% and 16.7%, respectively). These findings suggest that under the conditions of the present study, ewe nutrition had little effect on maternal behaviour. However, lambs born to ewes offered 2 cm pasture sward heights during mid and/or late pregnancy (2-2, 2-4 and 4-2 treatments) displayed behaviour that demonstrated greater 'need' whereas lambs born to ewes offered 4 cm during mid and late pregnancy sought less attention from their dam.     

Genetic analysis of emotional reactivity in sheep: effects of the genotypes of the lambs and of their dams

A total of 1347 weaned lambs from eight genotypes were tested over five consecutive years: Romanov (ROM) and Lacaune (LAC) pure breeds, the two F1 crossbreeds (RL and LR) and the offspring of ewes from these four genotypes sired with Berrichon-du-Cher rams (BCF). The lambs were individually exposed to three challenging tests involving novelty, human contact and social isolation. Ten synthetic variables were used to express social reactivity (i.e., active vs. passive strategy), exploratory activity and reactivity to humans. BCF crossbreds were more active (i.e., high bleats, locomotion and attempts to escape) than purebreds and F1. In contrast, ROM expressed more passive responses (i.e., low bleats and vigilance postures) than LAC and BCF crossbreds. In addition, ROM approached a motionless human less and had longer flight distances to an approaching human than did LAC and BCF crossbreds. When restrained, ROM, and to a lesser extent B×ROM and B×LR, avoided human contact more than did LAC, RL and B×LAC. Most of these differences were explained by direct additive genetic effects while maternal influences or heterosis effects were rarely significant. The highest heritability was for high bleats (h² = 0.48). Females were more active and avoided human contact more than did males.     

Factorial correspondence analysis of fear-related behaviour traits in Japanese quail

Factorial correspondence analysis was performed on 341 quails from a F2 cross between two lines divergently selected on the duration of tonic immobility over 29 generations. Several fear- or stress-related traits were recorded, i.e. tonic immobility duration, number of inductions needed to induce tonic immobility, open-field behaviour (time spent walking, latency before first movement and number of defecations), asymmetry of tibia lengths and corticosterone concentration after restraint stress. Variables were categorised in classes and analysed by factorial correspondence analysis. The first axis was mostly described by open-field behaviour, and the second by tonic immobility traits (duration of tonic immobility and number of inductions), which showed that these behaviours were almost independent. No relationship was found between axes of the factorial correspondence analysis and corticosterone concentration or asymmetry of tibia lengths, showing that these variables reflected other characteristics of stress susceptibility than those described by tonic immobility and open-field behaviour. These results show that reaction to stress of quails is a multidimensional trait and cannot be summarised by one trait.     

Association of sedentary behaviour with metabolic syndrome: a meta-analysis

Background

In recent years there has been a growing interest in the relationship between sedentary behaviour (sitting) and health outcomes. Only recently have there been studies assessing the association between time spent in sedentary behaviour and the metabolic syndrome. The aim of this study is to quantify the association between sedentary behaviour and the metabolic syndrome in adults using meta-analysis.

Methodology/Principal Findings

Medline, Embase and the Cochrane Library were searched using medical subject headings and key words related to sedentary behaviours and the metabolic syndrome. Reference lists of relevant articles and personal databases were hand searched. Inclusion criteria were: (1) cross sectional or prospective design; (2) include adults ≥18 years of age; (3) self-reported or objectively measured sedentary time; and (4) an outcome measure of metabolic syndrome. Odds Ratio (OR) and 95% confidence intervals for metabolic syndrome comparing the highest level of sedentary behaviour to the lowest were extracted for each study. Data were pooled using random effects models to take into account heterogeneity between studies. Ten cross-sectional studies (n = 21393 participants), one high, four moderate and five poor quality, were identified. Greater time spent sedentary increased the odds of metabolic syndrome by 73% (OR 1.73, 95% CI 1.55–1.94, p<0.0001). There were no differences for subgroups of sex, sedentary behaviour measure, metabolic syndrome definition, study quality or country income. There was no evidence of statistical heterogeneity (I² = 0.0%, p = 0.61) or publication bias (Eggers test t = 1.05, p = 0.32).

Conclusions

People who spend higher amounts of time in sedentary behaviours have greater odds of having metabolic syndrome. Reducing sedentary behaviours is potentially important for the prevention of metabolic syndrome.     

Inter-Individual and Inter-Strain Variations in Zebrafish Locomotor Ontogeny

Zebrafish exhibit remarkable alterations in behaviour and morphology as they develop from early larval stages to mature adults. In this study we compare the locomotion parameters of six common zebrafish strains from two different laboratories to determine the stability and repeatability of these behaviours. Our results demonstrate large variability in locomotion and fast swim events between strains and between laboratories across time. These data highlight the necessity for careful, strain-specific controls when analysing locomotor phenotypes and open up the possibility of standardising the quantification of zebrafish behaviour at multiple life stages.     

Behaviour of laboratory mice in different housing conditions when allowed to self-administer an anxiolytic

Standard cages prevent mice from performing several natural behaviours for which they are motivated. As a consequence, abnormal behaviours sometimes develop and mice often spend long periods inactive. To improve welfare, cages are sometimes furnished with items such as nesting material, shelters and running wheels. We have previously reported that when allowed to self-administer an anxiolytic, mice in furnished cages consume less anxiolytic than mice in standard cages. This paper presents the results of behaviour studies of the mice in the same experiment. Female C57BL/6J mice (3 per cage) were housed in Standard (n = 10), Unpredictable (n = 10) or Furnished (n = 6) cages. Unpredictable cages were identical to Standard cages, but were exposed to unpredictable events two to three times a week. Furnished cages were double the size of Standard cages and contained nesting material, nest box, tubes, chew blocks and a running wheel. During three consecutive periods, mice had access to only water (control), water or an anxiolytic solution on a daily alternating schedule (forced consumption), and finally, both water and anxiolytic (self-administration). Behaviour was analysed from video recordings taken during the dark phase. The housing type affected behaviour both under the control and the self-administration conditions. Overall, mice in Furnished cages spent less time resting and performing bar-related behaviours and more time on exploratory/locomotory behaviours. Mice in Furnished cages also performed less bar-circling stereotypies than mice in Standard cages. The Unpredictable treatment did not significantly affect behaviour compared to mice in the Standard conditions. There was an overall effect of anxiolytic availability on rest-related behaviours and on exploration-locomotion behaviours, in that mice rested more and spent less time on exploration and locomotion when they were able to self-administer the anxiolytic.     

Male dominance status,female choice and mating success in the brown lemming, Lemmus trimucronatus

The objective of this study was to determine whether female brown lemmings would selectively mate with dominant conspecific males. In dyadic encounters, oestrous females paired with dominant males engaged in more frequent lordosis and contact social behaviours than those paired with subordinate males. However, the mount and thrust scores of dominant and subordinate males did not differ significantly. When females had simultaneous access to tethered dominant and subordinate males, they spent more time in close proximity to dominant males and avoided contact with subordinate males. Copulation scores were higher with dominant males. In triadic encounters with free-moving dominant and subordinate males, oestrous females spent more time near, and engaged in more sexual behaviour with, dominant males. Intermale agonistic interactions resulted in ‘privileged access’ to females by dominant males. Sexual behaviour scores were lower and there was a 10-fold increase in intermale aggression in triadic encounters between females and unfamiliar dominant and subordinate males. Both intermale agonistic interactions and female ‘choice’ behaviour accounted for the differential copulatory success of dominant males.     

Do pigs find a familiar odourant attractive in novel surroundings?

Sixty-four DurocxLandrace pigs (Sus scrofa) of both sexes were reared from birth to 6 weeks of age in either fresh air or an atmosphere containing an artificial odourant (Ambi-Pur). Their behavioural responses to a novel environment (a modified open field) were then observed over 1h when the test arena contained either the familiar Ambi-Pur odourant or ammonia gas at 45ppm. Although members of other mammalian and avian species are attracted to familiar odours in otherwise novel surroundings, the presence of Ambi-Pur had no effect on the pigs' readiness to enter the novel arena from a sheltered area or on other fear-related behaviours following entry (p>0.05). Pigs kept in fresh air from weaning until test were generally less active and spent less time at the centre of the open field if the test was carried out in an ammoniated atmosphere rather than fresh air; this suggests that they found ammonia aversive. On the other hand, the presence of ammonia at test accelerated approach to the centre of the open field and increased the number of entries into that area and the percentage of time spent there as well as overall activity in pigs that had also been exposed chronically to this gas at 43ppm from weaning until testing at 6 weeks (p<0.05). Thus, after chronic exposure to either ammonia gas or an artificial odourant, ammonia was the only stimulus that appeared to act as an attractive agent for pigs placed in an otherwise novel environment.     

Influence of Inter-Lake Variation in Natural Nest Predation Pressure on the Parental Care Behaviour of Smallmouth Bass (Micropterus dolomieu)

Predation risk has the ability to greatly influence the behaviour of reproducing individuals. In large long-lived species with low risk of predation for parents, reproductive behaviours often involve caring for offspring (i.e. defending broods from predators) and these behaviours are essential for offspring survival. Our objectives were to test for the presence of natural variation in nest predation pressure in an aquatic environment for a species that provides sole-paternal care, smallmouth bass ( Micropterus dolomieu ), and to determine if natural variation in predation pressure influences parental care behaviour. We used snorkeler observations and a series of metrics to assess predation pressure and parental care behaviour in six lakes within a narrow geographical range. Lakes differed in all predation pressure metrics: number of predators in proximity to nest when males were present, time to predator arrival and number of predators that consumed eggs when males were absent and total number of nests that was preyed upon. Similarly, parental behaviour varied between lakes. Parental smallmouth bass spent more time engaged in anti-predator defences in lakes with high predation pressure, while males from low predator pressure lakes remained close to their nest. Conversely, males from lakes with low and high predation pressure showed a similar willingness to defend their nests during simulated nest predation events. Our results show that natural variation in aquatic nest predation pressure across multiple lakes can be significant and has the ability to influence baseline parental care behaviour. Such variation provides opportunities to study the costs and consequences of parental care and to evaluate how this could influence demography and community interactions in aquatic systems.     

The behavioural, physiological and immunological responses of lambs from two rearing systems and two genotypes to exposure to humans

The behavioural, physiological and immunological responses of lambs from two rearing systems and two genotypes to exposure to humans was assessed during and immediately after testing in an open-field arena. Ninety-six lambs of two genotypes (Scottish Blackface: BF and Texelx(Blue-faced LeicesterxScottish Blackface): T) were used. From birth to weaning one of two management regimes was applied: extensive (E), whereby animals were handled as little as possible or semi-intensive (I), in which lambs experienced a greater level of human exposure. Eight lambs from each of the four treatment groups received an antigenic challenge (Mycobacterium a. paratuberculosis) at 9 weeks of age to allow subsequent testing of immunological reactivity. At 1 and 3 weeks after weaning and 1 year later, lambs were tested in groups of four in a 4.5x4.5 m indoor arena, marked with gridlines at 0.75 m intervals. There were a number of occasions where testing revealed significant effects of genotype, management or their interaction, but in an approximately equal number of instances no significant effects of either genotype or management were observed. Genotype significantly influenced the number of squares occupied in the test arena over a 10-min period before the human entered (100.4 vs. 110.5; sed 2.70 for BF and T lambs, respectively, p<0.001). In relation to the number of new squares entered, there was a genotypexmanagement interaction: BFE lambs entered fewer squares than TE lambs but following semi-intensive management (I) BF lambs entered more squares than T lambs (p<0.05). When a human entered the arena after this 10-min period, while there was a gradual reduction in the number of animals which had not moved over the next 5 min, 66 animals had not moved within the allocated time. Also during this period, BF lambs stood facing the human for significantly longer than T lambs (p<0.05). At the time of arena testing, 12 lambs from each treatment group were fitted with heart-rate monitoring equipment. There were significant differences in heart rate in relation to period of testing, i.e. before (107.9) or after (112.3) the point at which the human entered the arena or when the lambs were walking in the presence of a moving human (126.3 b.p.m.; sed 2.15, p<0.001). When lambs were alone in the test arena, BF lambs had higher heart rates than T lambs (p<0.05). The heart rate of E lambs increased more than that of I lambs when the human entered the pen (9.4 vs. 0.3 b.p.m.; sed 3.95, respectively; p=0.05). Immediately following completion of the behavioural tests, blood samples were collected from subsets of lambs. Plasma cortisol concentrations of BF lambs were greater than those of T lambs (82.0 vs. 53.5 nmol/l; sed 10.18, p<0.01) but there was no effect of management. Blood samples collected from the lambs challenged with a novel antigen prior to weaning showed a genotype but not a management effect on both antibody and cell mediated immune responses, although there was a genotypexmanagement interaction. However, it should also be noted that there were no significant effects of either genotype or management on a number of the indices recorded: latency of lambs to move from the initial entry position in the absence or subsequent presence of a human; length of time one individual was separated from the other three; distance moved in a raceway before stopping; plasma beta-endorphin concentrations; heart rate in the presence of a human. Overall, these results suggest that although differences in responsiveness associated with specific genotypes of sheep can be detected in a test situation, the early life management regime may also have an effect. The results of this study caution against drawing conclusions between studies where different genotypes are employed.